Pakistani Prime Minister Nawaz Sharif has ordered all international aid agencies to renew their registration within 90 days amid a crackdown on charity workers whom authorities accuse of breaking unspecified laws.

Last week, authorities said they would tighten oversight of local and international aid groups. Police closed the offices of the international aid organization Save the Children but did not explain why.

"All INGOs [international nongovernmental organizations] will complete the process of their fresh registration with the Government of Pakistan within three months," said a government statement.

Save the Children has operated in Pakistan, a poverty-stricken South Asian nation of 190 million people, for more than 30 years.

But it has had tense relations with the government since 2011, when a Pakistani doctor, Shakil Afridi, was recruited to help the CIA hunt down Osama bin Laden.

Last week's decision to shut down Save the Children was suspended two days later after international donors, including the U.S. government, raised concerns.